WILLIAM McBRIDE, the Australian doctor who first alerted the world to the dangers of the thalidomide drug, was found guilty of scientific fraud yesterday over his experiments with another anti-morning sickness drug, Debendox.

After one of the longest inquiries in medical history, a tribunal in Sydney found against Dr McBride in four out of seven allegations that he had misrepresented results of his experiments with a component of Debendox in which he had set out to prove that the drug, like thalidomide, caused birth deformities.

The Medical Tribunal of New South Wales, headed by Judge Brian Wall, accused Dr McBride of 'deliberately selecting and culling data' and of 'reprehensible' conduct in his experiments. It described the affair as 'a sorry saga' which should have been avoided. At the same time, it cleared him on eight separate complaints relating to his work as one of Australia's most prominent obstetricians.

Dr McBride, 65, who sat calmly in Sydney's Supreme Court as the findings were announced, declined later to comment. The tribunal will hear further evidence later this year when it decides whether he will be allowed to practise medicine.

Once a darling of Sydney society, and feted internationally over his thalidomide breakthrough, Dr McBride has undergone one of the most spectacular falls from grace the medical world has seen.

His letter to the Lancet in 1961, following his observations of pregnant women in his Sydney practice, is regarded as the first public warning that thalidomide, a sedative, could cause terrible deformities in babies of women who took it during pregnancy.

It led to withdrawal of the drug and an avalanche of legal cases in the Seventies against Distillers, the company which marketed it in Britain and Australia. Dr McBride used some of the money from awards and honours heaped on him in Britain, France and Australia to set up Foundation 41, a private Sydney research institution, to study causes of mental and physical handicaps in babies.

It was a Foundation 41 experiment which led to yesterday's verdict. His target was Debendox, a morning sickness drug marketed by Merrell Dow of the US. He set out to show that Debendox also caused birth deformities. In 1982, he published a paper on experiments on rabbits with hyoscine, a Debendox component, which appeared to support his hypothesis.

Merrell Dow took Debendox off the market in 1983 in the wake of suits from parents and children in Britain, the United States, Germany and Australia who claimed it caused birth defects. Dr McBride appeared as an expert witness against Merrell Dow in some of these cases. Although there are still scientific arguments for and against Debendox, yesterday's verdict will be a setback to plaintiffs against the drug.

The case against Dr McBride was sparked when one of his research assistants resigned after discovering the doctor had changed some original figures. The row became public four years later when Norman Swan, a British-born paediatrician, produced a radio programme for the Australian Broadcasting Corporation accusing Dr McBride of scientific fraud.

An inquiry initiated by Foundation 41 and headed by a former chief justice concluded in 1988 that Dr McBride was guilty of scientific fraud in that he published statements which he knew were untrue. That inquiry was essentially a private one, with no power to censure or punish Dr McBride.

The medical tribunal inquiry which reported yesterday was initiated by the complaints unit of the New South Wales Health Department. Its hearings began in 1989 and were meant to last six weeks. They turned into a bureaucratic and legal monster, involving a parade of disagreeing expert witnesses focusing largely on questions of scientific procedure and the politics of childbirth.

Over the past five years, Dr McBride's once fashionable Sydney practice has collapsed to almost nothing and he has been forced to sell family properties to pay for his defence. His supporters say the length and conduct of the hearings have denied him natural justice.

Dr McBride admitted in a statement to the medical tribunal that he had altered data about drug dosages given to rabbits, and had taken 'short cuts which a scientist should not take and, as a result, in publishing material which was false and misleading, and I regret this'.

Privately, he has always asserted that big international drug companies were behind his downfall, and that he was a victim of a conspiracy. 'It's all very well to talk about perfect scientific protocol,' he once said. 'Drug companies have a vested interest in keeping their drugs on the market. I have a vested interest in protecting unborn babies. It's as simple as that.'